Institute of Environmental Engineering & Nano-Technology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong, China.
Institute of Research and Development, Duy Tan University, Danang 550000, Viet Nam.
Sci Total Environ. 2020 May 20;718:137291. doi: 10.1016/j.scitotenv.2020.137291. Epub 2020 Feb 13.
In biological wastewater treatment systems, extracellular polymeric substances (EPS) are continuously excreted as a response to environmental changes and substrate conditions. It could severely affect the treatment efficacy such as membrane fouling, dewaterability and the formation of carcinogenic disinfection by-products (DBPs). The heterogeneous dissolved organic matter (DOM) with varying size and chemical nature constitute a primary proportion of EPS. In the last few decades, fluorescence spectroscopy has received increasing attention for characterizing these organic substances due to the attractive features of this low-cost spectroscopic approach, including easy sample handling, rapid, non-destructive and highly sensitive nature. In this review, we summarize the application of fluorescence spectroscopy for characterizing EPS and provide the potential implications for online monitoring of water quality along with its limitations. We also link the dynamics of fluorescent dissolved organic matter (FDOM) in EPS with operational and environmental changes in wastewater treatment systems as well as their associations with metal binding, membrane fouling, adsorption, toxicity, and dewaterability. The multiple modes of exploration of fluorescence spectra, such as synchronous spectra with or without coupling with two-dimensional correlation spectroscopy (2D-COS), excitation-emission matrix (EEM) deconvoluted fluorescence regional integration (FRI), and parallel factor analysis (PARAFAC) are also discussed. The potential fluorescence indicators to depict the composition and bulk characteristics of EPS are also of interest. Further studies are highly recommended to expand the application of fluorescence spectroscopy paired with appropriate supplementary techniques to fully unravel the underlying mechanisms associated with EPS.
在生物废水处理系统中，细胞外聚合物物质（EPS）会不断地被排泄出来，以应对环境变化和底物条件。这可能会严重影响处理效果，如膜污染、脱水性能和致癌消毒副产物（DBPs）的形成。具有不同大小和化学性质的异质溶解有机物（DOM）构成了 EPS 的主要部分。在过去的几十年中，由于这种低成本光谱方法具有吸引人的特点，包括易于处理样品、快速、非破坏性和高度灵敏的性质，荧光光谱学在这些有机物质的特性描述方面受到了越来越多的关注。在这篇综述中，我们总结了荧光光谱学在 EPS 特性描述中的应用，并提供了在线水质监测的潜力及其局限性。我们还将 EPS 中荧光溶解有机物（FDOM）的动态与废水处理系统中的操作和环境变化联系起来，以及它们与金属结合、膜污染、吸附、毒性和脱水性能的关联。我们还讨论了荧光光谱的多种探索模式，如带有或不带有二维相关光谱（2D-COS）耦合的同步光谱、激发-发射矩阵（EEM）解卷积荧光区域积分（FRI）和平行因子分析（PARAFAC）。描述 EPS 组成和整体特征的潜在荧光指标也很有意义。强烈建议进一步研究扩展荧光光谱学与适当的补充技术的应用，以充分揭示与 EPS 相关的潜在机制。
